Guys, have problems with kik on my LS 400 98 ucf 20/21. some time ago i had problems with check vsc. i installed throttle from celsior(japan-the problem was solved . but now when i kik my pedal rpm reachs only to 5000 and and then it is breakdown sharply. I have no cheks. whats the matter???

 

What is "kik down"?

 

Sounds like the throttle unit is not quite good or does not match to your car.
Measure the resistances of 2 sensors below attached to the throttle body.

The throttle position sensor should show around 1.8 kΩ between terminals 1 and 4. Also check the resistance change of terminals 2 and 3 rotating the valve and confirm there's no abnormal resistance jump or glitch.

The similar thing can be said to the accelerator position sensor, but the resistance should be about 2.5 kΩ between terminals 3 and 4. Also check the resistance change of terminals 1 and 2.